How to Survive a Tsunami

Tsunami waves stay small until they reach shallow waters.

You may think tsunamis are impossible to survive if you’ve seen videos of elevated tides rushing toward a shoreline filled with people. Following a massive earthquake, tumultuous, powerful water covers the shoreline and beach, overpowering bystanders and seawalls. Once you have information about the causes and signs of an impending tsunami, you won’t fear for your life at the beach.

The most massive waves start in the Pacific Ocean, a prime tsunami risk area, and flood as far as ten miles inland, causing flooding, destruction, and death. With the right tsunami information, it’s possible to stay safe and help others to safety on higher ground as well. This guide will help you learn warning signs so you remain aware in dangerous regions and know what to do when a tsunami happens. This survival guide will not only tell you how to survive a tsunami, but also tell you what they are, what causes them, and how to recognize one coming.  

Posted signs warn of tsunami danger zones.
Posted signs will let you know when you’re in a tsunami danger zone.

Tsunami Fast Facts 

Giants waves are an impressive force of nature, on a par with earthquakes, volcanos, and hurricanes. Their power is tough for people to believe but should impress on you how important it is to be far away from the shoreline following an earthquake when a tsunami might strikes. Here’s some basic information before we tell you how to survive a tsunami:

  • Get to higher ground during a tsunami.
  • Stay away from the shore following an earthquake.
  • People cannot out-swim or outrun a tsunami wave. Grab hold of something stationary, like a tree, or something that floats like a raft and wait for help. 
  • Eighty percent of tsunamis occur in the Pacific Ocean because of the number of active earthquake zones. But risk zones also exist in both the Mediterranean and Caribbean Oceans. 
  • The wave of a tsunami can reach over 100 feet in height.
  • Tsunami detection buoys throughout the oceans trigger the Tsunami Warning System, a siren and strobe light on the shore that signals a tsunami is coming. 
  • The first in the series of waves is the smallest and weakest of a tsunami; subsequent waves are much more dangerous. 
  • A tsunami wave travels as fast as an airplane, as much as 600 miles per hour across the ocean.
  • Once the wave hits the shore, it slows to the speed of a car, between 20 and 30 miles per hour. 
An example of the devastation tsunami wave series can wreck on coastal towns.
Devastation left in the wake of a tsunami wave.

What is a Tsunami

The word tsunami is Japanese. It describes a series of waves that can reach over 100 feet tall and travel at speeds up to 600 miles per hour across the sea. Japan’s position in the Pacific Ocean has made it susceptible to frequent tsunamis throughout history.

A single wave in a tsunami can be implausibly long, as much at 60 miles. That’s why it’s crucial to stay away from the shore, get inland, and find higher ground when you hear a tsunami siren. Wave series will go on for days, with as much as an hour in between crests. Once a tsunami begins, seek out information in the community on the radio or from cell phone alerts to learn when the danger has passed.

Following an earthquake, a series of waves will cross thousands of miles in the Pacific Ocean without losing force. When submarine earthquakes happen in the middle of the sea, tsunamis travel out in every direction from that origin point. A tsunami in the Indian Ocean traveled over 3,000 miles to the coast of Africa, destroying property and killing people once it reached the shore. Out on the ocean, they’re under a foot tall, unnoticeable to sailors and sea vessels. But when the wave reaches the beach, the surface water moves faster than the bottom, causing the water’s rapid rise. 

A tsunami’s behavior is unpredictable, from the size of the waves to the number and duration. That’s why it’s essential to learn the early warning signs when you learn how to survive a tsunami. After an earthquake or during a tsunami warning always stay away from the shore. Even if the series of waves is mild in your area, they may devastate other nearby beaches. If you are caught outdoors or on the beach during a tsunami, don’t panic. 

Waves carry boats far inland, leaving them amongst destroyed buildings.
Debris is left behind after flood waters retreat back to the ocean.

How to Survive a Tsunami on the Beach

Your best chance for surviving a tsunami on a beach is to pay attention to the warning signs, stay away from the shore after an earthquake, and get to high land out of the hazard zone. Then wait for information from disaster response groups. Whether you’re visiting or living in a tsunami zone, learn where the closest evacuation point is out of the tsunami’s reach. With your family, discuss how you’ll reach the evacuation area and reconnect if you’re separated from your people.

The sooner you know a tsunami is coming, the better your chance of evacuating the beach and making it to higher ground. If it’s too late, and the water’s already rising, here’s what to do in a tsunami:

  • Make it as far inland as you can, over a mile. 
  • Head for high ground, get at least 100 feet above sea level.  
  • Grab ahold of something stationary, like a tree or something that float, like a raft. 
  • If you’re in a boat, head further out into sea away from the shoreline. 
  • Don’t swim against the current, grab ahold of something stationary, or that floats.

As you learn how to survive a tsunami, remember the first crest in a series of waves is the smallest and weakest. The waves following an earthquake may continue for hours or up to a day. If you’re in a boat at the beach, head out into the ocean. You’ll stand a better chance away of survival away from the shoreline. Strong currents and rising water can drag boats into collisions with bridges and buildings. 

The waves will recede into the sea with currents just as strong as when they hit the shore. If you’re holding onto something table, don’t let your guard down when the water recedes. Hold tight, and as soon as it’s safe to move, head inland to at least a mile from the shore and 100 feet over sea level. 

Even high in buildings above the shore, rising waters can still cause devastation.
Most flood waters rise around ten feet, but can reach depths of up to 100 feet.

Early Tsunami Warning Signs

There are two kinds of warnings you get when a tsunami is coming. Natural signs are the first indication you may be in danger. By learning to recognize these warning signs, you’ll be well on your way to safety when the second warning, the official tsunami siren, starts. When you’re in a tsunami region, an earthquake may be the first signal a tsunami is on its way. Scientists use a Tsunami Warning System around the world to collect information that helps them to predict where tsunamis will hit coastlines, how severe they will be, and how long the series of waves will last.

If you’re at the beach when an earthquake hits, drop to the ground and avoid falling objects and debris. If possible, shelter under something stable. Keep an eye out and avoid fallen power lines, buildings, and vehicles. When the shaking stops, pack up for the day and head inland. Don’t wait for further warning signs or the siren to sound. 

Sometimes the earthquake takes place further out in the ocean, away from where people can feel it. Earthquakes hundreds of miles away from the coast can still cause a tsunami. Here are a few other signs a tsunami is coming:

  • The ocean pulls away from the shore, exposing the ocean floor.
  • A roaring sound is coming from the ocean, like a freight train or rushing water. 
  • The ocean suddenly rises, and a wall of water pushes onto the shore. 

If any of these phenomena happen, don’t go exploring. Quick action is the most important part of how to survive a tsunami. Get somewhere at least 100 feet above sea level and a mile inland. It’s better to practice excessive caution than get caught in the first wave of an unstoppable wall of water. 

If you ignore early warning signs and the tsunami siren, the first wave may be moderate, flooding only the beach without cresting the seawall. However, the first rush of water in the tsunami is often the weakest. The wave series can continue for hours or even an entire day after an earthquake. 

Boats end up far from the water, carried by the raging tide.
Following a tsunami wave series, ships end up far inland carried by flood waters.

Will You Survive a Tsunami in a Pool?

Maybe you’ve seen footage of tsunamis hitting the shore and figured out how to survive a tsunami by jumping into a seaside pool for safety. You’ll just hold your breath underwater and wait for the chaos above you to subside. Even with record-breaking lung capacity, you haven’t improved your chances of survival over other people onshore. There are a few reasons the pool isn’t any safer than dry land during a tsunami event. 

First, you might think about how you dive under traditional waves in the ocean to swim out past where they’re breaking to calmer water. You can avoid the tumultuous wave crest by diving. There’s still water just a few feet beneath the surface. But tsunami waves differ from traditional waves in that they don’t exist on just the water’s surface. Instead, they exert force down to the seafloor, dragging sand and sea life with them inland. You may have noticed silt and mud covering streets, buildings, and cars in the wake of a tsunami. The force of the wave will just scoop up the pool water, carrying you along with it as it continues to travel inland. 

Underwater, you’ll have trouble orienting yourself. The current will drag not only you but also other people and debris like furniture, wreckage from homes and buildings, boats, and cars. You won’t be able to see in the murky water and may get knocked unconscious or injured by colliding with wreckage. If you make it to the surface, you may feel tempted to out-swim the wave. The current will be just as strong at the top of the wave as when it pulled the pool water and you with it. Instead of wasting energy trying to swim, float with the current and look for a potential raft. 

Hold on to anything that floats and try to grab ahold of something stationary. There are still people missing from the 2004 tsunami in India because the current dragged them back out to sea. It’s crucial to hold on to something as the force of the first wave recedes into the ocean. So no, you can’t hide in a pool.

Tsunami waves easily overwhelm sea walls and cause coastal flooding.
Waves overpower sea walls during a tsunami event.

Can you Dive Under a Tsunami?

It’s tempting to think if you’re a powerful swimmer, you can just dive under a tsunami as it hits the shore. But experiencing a tsunami is less like being in the ocean and more like getting caught in severe flooding. Regular waves travel much slower than tsunami waves, hitting the shore at a rate between one mph and five mph. That’s why you see surfers able to paddle along with a crest of a wave before jumping onto their surfboard to ride it. 

There’s also no under of a tsunami. Unlike waves that travel along the surface water, the tsunami reaches the shoreline’s ground. If you attempt to swim beneath the surface, you’ll encounter more fast-moving water. That is also why tsunami waves are murky when they hit the shore. They stir up the seafloor as they travel, bringing sand and sea life with them. 

For fast-moving tsunami waves, people can’t swim along with the crest. The fastest swimmer on Earth, Michael Phelps, can only reach six mph during a 100-meter butterfly sprint. And that’s in prime conditions in an Olympic pool. During a tsunami, strong currents swirl beneath the surface of the water, displacing sand, sea life, and debris. By trying to swim beneath the wave, you lose visibility, put yourself at risk for colliding with debris, or dragged further beneath the water’s surface by a current. 

That’s why your best bet is to grab ahold of something stationary and wait for the wave series to stop. If that’s impossible, grab ahold of floating debris instead of struggling to swim against the current. 

Debris fills tsunami waters as they flood inland.
Cars, debris, and trees get swept away with even moderate flood waters.

What Causes Tsunamis?

The most common causes of tsunamis are submarine earthquakes, underwater volcanic activity, landslides, and shifting tectonic plates between the ocean floor. That’s why the Pacific Ocean is a tsunami risk zone. It has more tectonic activity than other oceans. A much less frequent cause is meteor crashes, which can also cause massive water displacement. Staying informed about tsunami-causing events in your area can help you avoid getting caught near the shore during a significant wave event. 

In general, an earthquake must rate be near the ocean, rate over 7.0, and less than 62 miles beneath the Earth’s surface to cause a tsunami. As the ocean floor moves up and down, it causes the ocean’s surface to move as well. Factors like the earthquake’s duration, the surface area, and the amount of water displaced contribute to the tsunami’s size and length. 

In the open ocean, tsunamis don’t look like giant waves. Even seasoned sailors would have trouble recognizing one was taking place. That’s why officials caution boats to stay out to sea during tsunami warnings. They’re much less likely to suffer damage than vessels in a harbor. Waves sometimes carry ships far inland or destroy in collisions with buildings and bridges. 

Sometimes weather events can cause tsunamis. Fast-moving air pressure disturbances can have the same impact on the water, generating the enormous wave series. However, weather, volcanos, and meteors are all far less common than earthquakes, which cause over 80 percent of all recorded tsunamis. 

Warning signs let beach visitors know what to do after an earthquake or if the tide suddenly drops.
Observe posted signs and always stay alert in tsunami hazard zones.

How to Survive a Tsunami? Stay Alert.

Especially if you’re on the coast of the Pacific Ocean, don’t disregard the threat of a tsunami. During the 2004 tsunami, people walked out away from the beach as the water receded, unaware of the freight train of water barreling toward them. You may have as much as five minutes head start as the water pulls away from the shore. Now that you know tsunami risk zones and what to do in a tsunami, you have time to evacuate the beach and head for higher ground. Don’t stop to watch the water rushing in, or record with your phone until you’re safe on high ground. And don’t return to the water’s edge until authorities say that it’s safe to do so. By keeping your wits about you, not panicking, and respecting the brutal force of nature, you can survive a tsunami.